Comparison of SiNx-based Surface Passivation Between Germanium and Silicon

Tutkimustuotos: LehtiartikkeliArticleScientificvertaisarvioitu

Abstrakti

(Ge) has attracted much attention as a promising channel material in nanoscale metal-oxide-semiconductor devices and near-infrared sensing because of its high carrier mobilities and narrow bandgap, respectively. However, efficient passivation of Ge surfaces has remained challenging. In this work, we study silicon nitride (SiNx)-based passivation schemes on Ge surfaces and compare our observations to Si counterparts. Our results show that instead of a high positive charge density (Qtot) that is found in SiNx-passivated Si samples, similar Ge samples contain a high amount of negative Qtot (in the range of 1012 cm-2). The maximum surface recombination velocity of the samples is shown to reduce by a factor of three in both Si and Ge samples by a post-deposition anneal at 400 °C. The SiNx-coated samples are capped with an atomic-layer-deposited aluminum oxide (Al2O3) layer, which reduces the midgap interface defect density (Dit) after annealing to 7×1010 cm-2eV-1 and 4×1011 cm-2eV-1 in Si and Ge, respectively. Interestingly, while the Al2O3 capping seems to have no impact on Qtot of the Si samples, it turns the stack virtually neutral (~-1.6×1011 cm-2) on Ge. The presented SiNx-based passivation schemes are promising for optoelectronic devices where a low Dit and/or a low charge are favored.
AlkuperäiskieliEnglanti
JulkaisuPhysica Status Solidi (A) Applications and Materials Science
Varhainen verkossa julkaisun päivämäärä20 jouluk. 2022
DOI - pysyväislinkit
TilaSähköinen julkaisu (e-pub) ennen painettua julkistusta - 20 jouluk. 2022
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

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